Bipolar high-voltage voltages, for example ±270 V bipolar DC voltage, are often required in aircraft. Generators and appropriate rectifiers are usually used to provide voltages of this type. U.S. Pat. No. 7,638,890 B2 discloses for example a high-voltage generator with a five-phase rectifier which provides a bipolar high-voltage DC voltage with mains-free power supply. US 2012/0025604 A1 discloses an electrical energy supply system for an aircraft with a three-phase generator which feeds technical loads and has an insulation monitor for monitoring high reference potential-to-earth impedances. WO 2011/098117 A1 discloses a voltage converter which uses a rectifier to provide a bipolar high-voltage DC voltage from a three-phase alternating voltage, and in which the reference potential is tapped at a neutral point of a neutral point wiring of three phase chokes.
In this respect, on the one hand undesirable fluctuations can be produced in the common-mode output voltage. Nowadays, fluctuations of this type are compensated by filter stages appropriately connected downstream of the rectifier.
On the other hand, measures have to be taken against the failure of the entire supply of DC voltage if one of the potential connections fails. This can be ensured, for example, by protective circuits between the connection poles and the reference potential.
However, there is a need for a bipolar high-voltage DC voltage unit, in which fluctuations in the common-mode output voltage can be reduced and the resilience against failure of one of the DC voltage potential connections is improved.